Bulbous bluegrass (Poa bulbosa) is an obscure species of Poa, described as a short-lived cool-season grass, and the only grass known to have true bulbs. See, for example, the USDA Plant Guide: Bulbous Bluegrass, available on the UDSA website: plants.usda.gov/plantguide/pdf/pg_pobu.pdf. Introduced into the United States from Europe prior to 1900, Poa bulbosa is a bluegrass having a bunching growth habit that is easy to identify from other bluegrasses because of its leafy flowerheads combined with bulbous florets (bulblets). While Poa bulbosa produces true florets as well as bulblets, seeds are rare, with regeneration of the plants almost exclusively through asexual means. (Gucker et al., 2007, Poa bulbosa. In: Fire Effects Information System [Online], USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, available at: fs.fed.us/database/feis/. Each of the clonal bulblets has the potential to form a new plant, identical in nature to the parent plant.
Attempts to cultivate selections of wild ecotypes of Poa bulbosa into a commercial turf grass have not been successful. The species was previously found unsuitable due to high variability, low germination, lack of persistence, and competition with companion grasses. Poa bulbosa is generally considered a weed to be eradicated.
Currently, there is no cool-season grass species, hybrid, or cultivar having sufficient qualities to be useful as a turf grass, for example as a cool-season component of a sports field. In particular, there is no cool-season grass having utility as a cool-season component for traditional turfgrass overseeding applications on sports fields, fairways, parks, home lawns, and golf course greens that are comprised predominantly of a permanent, warm-season species. There is a need for uniform, reliable varieties of grasses suitable as persistent turfgrass, and particularly useful as a permanent cool-season component in turfgrass overseeding application and having acceptable characteristics for turf, including compatibility with a warm season grass.